Evaluation of a Thyroid Nodule

Abstract

Thyroid nodules are a common finding in the general population. The reported prevalence of nodules varies based on the epidemiologic methods for evaluation. The ranges for the prevalence are reported to be 2–6% with palpation, 19–35% with ultrasound, and 8–65% in autopsy data (Dean and Gharib, Best Pract Res Clin Endocrinol Metab 22:901–911, 2008). Although there is no known environmental risk factor for the development of thyroid nodules, there has been a notable increase in the incidence of thyroid nodules and thyroid cancer in the United States over the previous three decades. This observation is explained by two known processes. First, the incidence of nodules increases with age. Second, the median age of the population in the United States has been increasing over the previous decades. Additionally, nodules are being identified more commonly on imaging studies performed for other reasons, as the sensitivity of computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) has increased and their use has increased with more accessibility in developed countries.

Once a nodule has been identified, a proper evaluation is necessary as the primary concern is the presence of thyroid malignancy. A stepwise, evidence-based practice is necessary to avoid unnecessary testing, procedures, surgeries, and stress on the patient. The fundamental goal of the evaluation is to assess the presence of thyroid malignancy and need for intervention. Important factors that will be discussed include the concept that not all nodules need to be biopsied, as delay in surgical intervention in small nodules, even if harboring a malignancy, has not shown to affect the long-term survival of the patient.